Suspicious items — including cellphones taped together and a phone taped to a bottle of Pepto-Bismol — are found in the pair's luggage, which was on a different flight.

Reporting from Washington — Two Yemeni men arriving in Amsterdam on a flight from Chicago were arrested Monday on suspicion of preparing a terrorist attack after peculiar items turned up in their luggage, Dutch officials said.

U.S. authorities asked the Dutch to make the arrests after discovering that one of the men had checked his luggage from Chicago to Dulles International Airport in Virginia, then taken a flight to Amsterdam, said a Dutch official, who asked not to be identified because of the sensitive nature of the case.

The luggage sent to Virginia on Sunday night contained a cellphone taped to a bottle of Pepto-Bismol, three cellphones taped together and several watches taped together, Dutch and U.S. officials said.

The owner of the luggage, Ahmed Mohamed Nasser al Soofi, a Yemeni citizen who lives in Detroit, also was carrying $7,000 in cash, said the Dutch official.

After sending his luggage to Dulles, Al Soofi was joined at Chicago's O'Hare International Airport by a second man, Hezem al Murisi, and the pair took United Airlines Flight 908 to Amsterdam. Air marshals were aboard that flight, according to a U.S. law enforcement official speaking on condition of anonymity because he was not authorized to speak publicly.

Al Soofi's luggage went to Virginia, apparently without officials realizing he was not aboard that flight. From there, his luggage had been scheduled to go to Dubai, then Yemen. But once authorities learned Al Soofi had taken a different plane, federal officials in Virginia ordered the aircraft back to the gate and removed Al Soofi's baggage. An inspection revealed no explosives.

In a statement Monday night, the Department of Homeland Security confirmed that authorities found "suspicious items" in checked luggage belonging to two passengers aboard a United flight from Chicago to Amsterdam on Sunday night.

"The items were not deemed to be dangerous in and of themselves, and as we share information with our international partners, Dutch authorities were notified of the suspicious items," the Homeland Security statement said.

U.S. officials said the matter was under investigation because of the types of items found taped together.

The arrests were first reported by ABC News.

Authorities' suspicions were aroused in Birmingham, Ala., where federal airport screeners stopped Al Soofi for an additional security check because he wore bulky clothing in the summer heat. Officials found the watches and the Pepto-Bismol taped to the cellphone, but because those were not banned items, he was permitted to board a flight to O'Hare. It was unclear what he was doing in Birmingham or how long he had been there.

In Chicago, the two men were searched and their luggage inspected. Again, officials found no banned items and allowed them to board the flight to Amsterdam.

Dutch authorities questioned the men Monday. The luggage that went to Dulles remained in the possession of U.S. officials, the Dutch official said.

No court appearance is expected for several days, the Dutch official said.